As young families all over Britain struggle to find homes, now averaging £250,000, Royal aides emphasised Kate and William were keen to keep public costs down

The public has shelled out 16 times the cost of the average UK home on structural work and bringing rooms up to “basic living standard” for them and baby Prince George, said Sir Alan Reid, Keeper of the Privy Purse.

They paid to have one of two kitchens done up themselves. The money came from the £36.1million Sovereign Grant given to the Monarch by the Treasury in 2013/14.

Added to £1.1million from the financial year 2012/13, that makes £4.5 million.

As young families all over Britain struggle to find homes, now averaging £250,000, Royal aides emphasised 32-year-olds Kate and William, were keen to keep public costs down.

One said: “It’s done to a very ordinary level. It’s not opulent. I think you would all feel at home there.”

The couple have also received a large sum from Prince Charles’ private funds to help with furnishings.

A royal spokesman said: “The work included significant costs for the removal of asbestos, new roof, overhaul of electrics and plumbing and internal building – and returning the residence to a living space.”